The present invention relates to bearing monitors and, more particularly to, an improved bearing monitor that has a sensor and a processor attached to a rotating component of a system supported by the bearing.
Bearings are commonly used to support rotating masses in many types of vehicles. Over the lifetime of the vehicle, bearings may endure hundreds of thousands or even millions of cycles. Eventually, bearings will fail because of repetitive cycles of stresses. Bearing failure can cause catastrophic results depending on when the bearing fails. Bearing failure in a collective head of a helicopter, for example, may cause the helicopter to crash if the bearing fails during flight.
Usually, however, bearings do not fail instantaneously. Cumulative wear gradually degrades bearing components, which may emit measurable indicators of imminent failure. It is known in the art that a worn bearing will emit vibrations in a frequency range at or above 1 KHz. Consequently, bearing monitors that trigger an alarm when a bearing emits frequencies in this range have been developed. These monitors usually have a sensing component to measure the frequency of a particular bearing and a processing component to analyze data sent from the sensing component.
Monitoring bearings in many vehicles is a relatively simple process because the bearing is fixed in the vehicle structure and the sensing component is mounted to or near the bearing. A signal from the sensing component is then sent to the processing component through wires or other direct connection. However, in aircraft having rotors, for example, the only structure available to mount a bearing monitor may be a rotating structure.
One solution that has been used to monitor bearings in rotating structures is mounting the sensing component on or near the bearing. The processing component receives the signal from the sensing component through a slip ring of the rotating structure. Although transmitting signals through the slip ring is common and usually effective, in the case of monitoring high frequencies above 1 KHz, undesirable noise generated by the rotating structure often degrades the signal from the sensing unit. Therefore, monitoring the bearing through the slip ring is unreliable and could be dangerous to the passengers and crew of the aircraft.
It would, therefore, be desirable to have an improved apparatus, method and system for monitoring bearings in rotating systems that does not require transmitting a signal through the slip ring.
The present invention is a bearing monitor that has a bearing sensor to monitor frequencies emitted by a bearing in a rotating component. The bearing sensor has an output to a processor. The processor is attached to the rotating component to process the output from the bearing sensor to output a digital or logical signal correlating to a condition of the bearing.
In one embodiment of the invention, a method of monitoring a bearing includes the step of sensing vibrations emitted by a bearing using a sensor mounted on a rotating component. The bearing sensor has an output. The method then includes the step of providing a processor attached to the rotating component to process the output from the bearing sensor to output a digital or logical signal.
In another embodiment of the invention, a system to monitor a bearing in a rotating component includes a housing that is attached to the rotating component. A bearing sensor attached to the housing monitors vibrations emitted by the bearing in the rotating component. The bearing sensor has an output. A processor attached to the rotating component processes the output from the bearing sensor outputs a digital or logical signal correlating to a bearing condition.